Conventionally, a hybrid vehicle is known which includes a first motor generator connected to an internal combustion, a second motor generator connected to a drive wheel, and a voltage-controlled battery connected to an inverter via a switch, for example. The inverter drives and controls each motor generator. Each motor generator performs a voltage adjustment when a connection of a plurality of battery modules included in the voltage-controlled battery is switched between a connection in parallel and a connection in series. In this way, the switch is released. (See, for example, Japanese Patent No. 4353093.)